In various applications there is a need for accurate, repeatable and reliable measurement of linear and/or rotary motion and position. For example, magnetic field sensors can be used for such linear and/or rotary motion and position sensing. For this purpose, for example, one or more permanent magnets may be attached to a magnetic encoder (target), and the magnetic field resulting from the encoder may be measured or sensed by one or more magnetic field sensors.
Some of today's magnetic field sensors make use of magneto-resistive sensors. Thereby, magneto-resistance denotes the property of a material or a multilayer device to change the value of its electrical resistance when an external magnetic field is applied to it. There are different materials and/or multilayer devices showing different types of magneto-resistance, including Anisotropic Magneto Resistance (AMR), Giant Magneto-Resistance (GMR), Colossal Magneto-Resistance (CMR), Tunnel Magneto-Resistance (TMR), or Extraordinary Magneto-Resistance (EMR). Magneto-resistive multilayer devices often come in a so-called spin-valve configuration comprising two or more conducting magnetic material layers, whose electrical resistance can change depending on the relative alignment of the magnetization in the layers.
New concepts for improved detection of the speed, position, or angles of a magnetic encoder call for robust magnetic field sensors capable of detecting simultaneously different magnetic field components generated or influenced by a magnetic encoder.